Railway traffic controlling apparatus



Jan. 7, 1941. G W BAUGHMAN 2,227,623

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Feb. 18, 1928 s Sheets-Sheet1 Hod] Daspazcher" Office Code Sen fi'nq INVENTOR Equzpmeni. q w, 139 uhm a n Jan. 7, 1941. G. w. BAUGHMAN 2,227,623

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Feb. 18, 1928 6 Sheets-Sheet2 fndz'wkiualCnf/rol Equzjnmani for 0120 Szaizon.

Fig. Z.

0114 INVENTOR 2 Jan. 7, 1941. G, w. BAUGHMAN 2,227,623

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Feb. 18, 1928 6 Sheets-Sheets INVENTOR 6 W. Ba 4/711 aux-M4 Fly. 5.

G. W. BAUGHMAN Fil'ed Feb. 18, 1928 L L LL L L L L LL L L L L L L L L LL L L IL L, EL

h] Y y E 6 Sheets-Sheet 6 INVENTORZ ER-W Patented Jan. 7, 1941 RAILWAYTRAFFIC CONTROLLING APPARATUS George W. ldaughman, Edgewood Borough,Pa.,

assignor to The Union Switch & Signal Company, Swissvale, Pa, acorporation of Pennsyl- Vania Application February 18, 1928, Serial No.255,375

97 Claims.

My invention relates to railway traffic controlling apparaltus, andparticularly to apparatus adapted for use in a centralized trafiiccontrol system for railroads for controlling trafiic governing devicesfrom a remote point, such as a dispatchers office, and for indicatingthe condition of such devices at said office. More particularly mypresent invention relates to apparatus of the type described in whichthe control and indication are effected by means of codes which aretransmitted and received by means of relays instead of the usual codetransmitting keys and code responsive selectors.

The apparatus of my invention is an improvement upon that disclosed in acopendin-g application for Railway traffic controlling apparatus, SerialNo. 254,690, filed Feb. 16, 1928, by Lloyd V. Lewis.

I will describe one form of railway traffic controlling apparatusembodying my invention, and

will then point out the novel features thereof in claims.

In the accompanying drawings, Figs. 1 and 2 when arranged with Fig. 1above Fig. 2, comprise a diagrammatic View showing one form of a portionof the apparatus located at the control ofilce for transmitting controlcodes. Figs. 3 and 4 when arranged with Fig. 3 above Fig. 4 comprise adiagrammatic view illustrating the equipment located at a field stationfor receiving control codes from the equipment shown on Figs. 1 and 2and for also sending codes to the control office. Figs. 5 and 6 whenarranged end to end with Fig. 5 on the left comprise a view showinganother portion of the ofiice equipment suitable for receiving codestransmitted from the station equipment illustrated on Figs. 3 and 4.

Similar reference characters refer to similar parts in each of theseveral views.

In general terms the apparatus embodying my invention comprises anormally closed line circuit which includes a source of energy and aplurality of line relays, one located at the control oilice and one ateach station which is controlled from t such office. This circuit is attimes supplied with different codes by periodically opening and closingthe circuit, whereupon the line relays at the olfice and at all of thestations are periodically energized and ole-energized. The system hereinillustrated is intended to utilize 4 digit codes, that is, codes made upof 4 groups of units, each unit representing one interruption andreclosing of the line circuit. In the particular form of apparatus hereshown, each digit may have any number of units from 1 to 5 and it willtherefore be seen that with 4 digit codes of this type it is possible toprovide 625 different codes.

Referring now particularly to Figs. 1 and 2, the reference character Ldesignates a line relay located at the ofiice and included in a normallyclosed circuit which also includes line wires i and '2 which extend tothe stations associated with the apparatus here described. When theapparatus occupies its normal condition in which it is illustrated inthe drawings, the master relay 10 OS is ole-energized and thetransmitter relay 0C is energized so that line wire I is connectedthrough back contact 3 of relay OS and front contact 4 of relay 0C,battery 5 and line relay 0L to line Wire 2. The reference characters OJand Cd! designate two relays, the circuits for which are illustrated onFigs. 5 and 6 of the drawings and the operation of which will bedescribed in detail hereinafter. For present purposes, it is sufilcientto state that these relays are normally de-energized but are arranged tobe energized when a code is being received at the office. The referencecharacter OLA designates a slow acting relay which is controlled by aback contact 6 of relay OS, current being supplied to this relay fromterminals X and Y of a source of energy not shown in the drawings.

Located at the office is a series of unit relays each designated by thereference character OD with a suitable distinguishing sufiix. The ofiiceis also provided with a series of digit relays each designated by thereference character OK with a distinguishing exponent. By means of atransfer relay 0E the digit relays OK are successively energized :byoperation of the unit relays OD as will The described in detailhereinafiter.

Located also at the office is aline finder designated in general by thereference character F and comprising a stepping magnet in which controlsa plurality of contact arms H, [2, l3, [4, I5 and l 6, each of whichco-operates with a plural ty of fixed contacts. Associated with the linefinder F are a plurality of individual control equipments, one for eachstation, and only one of whichis shown complete in the drawings. Thiscontrol equipment comprises, in the form here shown,

a manually operable switch control lever to having a normal or left-handposition and a reverse or right-hand position. Associated with lever wis a signal control lever 1" having left-hand, middle and right-handpositions. The levers w and r control a series of start relays eachdesignated by the reference character OH with a distinguishing sufiixand a series of stop relays each designated by the reference character Gwith an appropriate suffix.

In explaining the operation of the apparatus shown on Figs. 1 and 2, Iwill first assume that lever w is moved to its reverse position. Whenthis happens, current fiows from terminal X, over lever w, wire H, backcontact l8 of relay 0G2,

wire 19, and winding of relay 01-12 to terminal Y. The start relay 0H2therefore becomes energized and closes front contacts 20 and 33. Theclosing of front contact 29 completes a circuit for the stepping magnetin of finder F which may be traced from terminal X, over front contact20 of relay 0H2, wire 2i, back contact 22 of relay 23, wire .24, andwinding of magnet ID to terminal Y. Magnet l3 therefore becomesenergized to move the armature 25 about the pivot 25 against the biasexerted by the spring 26. This lifts the pawl 2! out of engagement withthe wheel 28 and also closes contact 29. Current then flows fromterminal X, over front contact 29 of relay 0H2, wire 2i, winding ofrelay 23, contact 29, wire 39, and back contact 3i of a relay 32 toterminal Y. Relay 23 then becomes energized to open back contact 22 andde-energize magnet ID. The spring 26 then returns armature 25 to itsoriginal position, causing the pawl 21 to engage wheel 28 and advancethis wheel and the contact arms associated therewith one step. The relay23 is slightly slow acting and at the expiration of a brief interval oftime following the opening of contact 29, back contact 22 of relay 23closes to re-establish the circuit for magnet l0, thereby causing thismagnet to advance the finder another step. This process continues, thecontact arms of the finder being advanced in step by step fashion, untilthe arm 15 engages a contact which is connected with terminal X. It willbe seen that different contacts associated with arm l may be 49connected with terminal X over front contacts of different start relaysso that the finder may be stopped in different positions, depending uponthe particular one of the startrelays OH which is energized. In thepresent instance, since relay 45 0H2 is energized, when arm l5 engagescontact 35 current fiows from terminal X, over front contact 33 of relay0H2, wire 34, contact 35 and arm l5 of finder F, through winding ofrelay 32 to terminal Y. Relay 32 therefore becomes energized, to openback contact 3| and hold relay 23 deenergized. As a result, the magnetI9 of the finder F is held in its energized condition by relay CH2, andthe finder remains at rest in the selected position as long as relay 0H2remains energized.

55 With relay 32 energized, terminal X is connected over front contact33 of this relay and wire 31 with each of the finder arms ll, l2, l3 andI4 so that the contact associated with each of these arms which the armthen engages is connected 60 with the terminal X. The finder arms II tol4 determine the code to be transmitted, the fixed contacts associatedwith these finder arms being connected to the vertical line wires shownat the right in Fig. 2 in such a Way as to provide a dis- 55 tinctivecode combination for each position of the 75 through back contact 39 ofrelay OJ,

finder switch. In the case described, the code is 2132, in which thefirst three digits identify the station associated with the individualcontrol equipment shown in Fig. 2, while the fourth digit determineswhich one of a plurality of possible operations is to be effected atthat station. The closing of front contact 36 of relay 32 also completesa circuit through wire 31. back contact 38 of relay Od2. at the top ofFig. 1, thence and winding of relay OS to terminal Y. Relay OS thereforebecomes energized, opening at back contact 3 thereof. the normallyclosed circuit including the line relays at each location. Relay OLtherefore becomes de-energized and the line relay at each remainingstation becomes deenergized. The opening of back contact 6 of relay OSinterrupts the circuit for relay CA but this relay is slow acting and arelatively long interval of time elapses before it closes its backcontacts. The breaking of back contact I of relay OS deenergized relayOC and this relay now releases. At the expiration of the time requiredfor relay 0A to release, the closing of back contact 8 of this relaycompletes a circuit for relay 00 over back contact 9 of relay OB. Whenrelay OA is deenergized, and relay 0C is energized, the line circuit isagain closed from line wire I, through front contact 3 of relay OS, backcontact 40 of relay 0A, and front contact 4 of relay 00. It will benoted however, that with relay OA de-energized, a circuit is completedfor relay OB from terminal X over back contact 4| of relay OA, wire 42,winding of relay OB, wire 43, front contact 44 of relay 00, wire 45, andback contact 46 of the transfer relay OE to terminal Y. Relay OB thenbecomes energized and breaks at back contact 9 thereon the circuit forrelay OC. The release of relay OC interrupts at front contact 44 thereonthe circuit just traced for relay OB so that after relay 00 drops, relayOB becomes de-energized to re-establish the circuit for relay OC,whereupon relay 0B again becomes energized to de-energize relay DC. Itwill be plain from the foregoing that relay 00 will be periodicallyde-energized and energized to open and close the normally closed linecircuit.

wires 5|, 52 and 53, front contact 54 of relay OD3.

andwinding of relay OD3 to terminal Y. Relays ODI and OD2 are slowacting, and remain closed during the continued operation of relay 0C.This operation continues, each of the unit relays OD being energized insuccession by the continued operation of relay 00, until transfer relayOE becomes energized. The circuits are so arranged that relay OE becomesenergized when there has been delivered to the line by operation ofrelay 0C sufiicient impulses to make up the first digit of the codewhich it is desired to send. In the present instance the code isdetermined by the position of the selector arms ll, l2, l3 and I4 onfinder F, which now occupy a position corresponding to that in which arml5 engages contact 35, and it will therefore be seen that when relay OD3becomes energized, current flows from terminal X, over front contact 36of relay 32, wire 31, contact arm ll of finder F, and the contactengaged thereby, wires 51 and 58, back contact 59 of relay 0K2, wire 60,front contact 6| of relay OD3, wires 62 and 63,- and winding of relayOE, to terminal Y. Relay OE then becomes energized and is subsequentlystuck up by current which flows from terminal X, over front contact 59of relay OD2, Wires 5| and 64, front contact 65 of relay OE, wire 66 andwinding of relay OE to terminal Y. But

with relay on energized, the circuit for relay OB is open at backcontact 46 of relay OE, so that when relay OB releases relay OC' picksup and remains energized to hold the line circuit closed. When relay 0Cis energized back contact 41 of this relay is open and after a timeinterval, relay ODI drops. The opening of front contact 48 of this relayde-energizes relay OD2 so that this relay also drops. The opening offront contact 50 of relay ODZ de-energizes relay OE, and alsodeenergizes any of the succeeding unit relays OD which may happen to bestuck up. In this case, relay OD3 is the only one energized and thisrelay now becomes de-energized. It will therefore be plain that in theparticular case here described the first digit of the code will be madeup of two units at the conclusion of which there is a pause amounting tothe time required for releasing relay OD-l plus the release time ofrelay OD2, plus the release time of relay OE. At the conclusion of thispause, that is, when relay OE becomes deenergized, relay OB again picksup to commence the intermittent operation of relay OC, and to deliverthe second digit to the line. The operation of the unit relaysdelivering the transmission of the second digit is the same as hasalready been described and will be understood without tracing thisoperation in detail. It should be pointed out, however, that when relayOE became energized, current was supplied to relay OKI over frontcontact $1 of relay OE so that relay OKI became energized and that thisrelay Was stuck up by current supplied from wire 31. over wire 69 andfront contact 10 of relay OKI, through a winding of the relay toterminal Y. Furthermore, when relay OE became de-energized, the closingof back contact 61 picked up relay 0K2 over front contact 13 of relayOKI and relay 0K2 is now stuck up over its own front contact 15. It willbe seen that with relay 0K2 energized, relay GE is controlled by acontact arm l2 of finder F. When the number of impulses have beendelivered to the .line in accordance with the second digit of the codewhich is to be sent, relay OE again becomes energized. Since in the codeillustrated the second digit comprises but one impulse, this takes placeas soon as relay ODI becomes energized, current then flowing fromterminal X, over front contact 35 of relay 32, wire 31, contact arm I 2and the contact associated therewith on finder F, wires 16 and 11, backcontact 18 of relay 0T4, wire 19, front contact of relay 0K2, wire BIand front contact Bl of relay OD! to wire 63 and thence through windingof relay OE to terminal Y. Relay OE becomes energized then, as soon asrelay OC has become de-energized the first time during the second digitof the code. When relay 00 next becomes energized, the relay ODZ becomesenergized and sticks up relay OE. At the end of the pause introduced bythe slow releasing relays ODI and OD2 the relay OC again begins tooperate to send the third digit. The release of relay ODl de-energizesrelay OE, and the operation of relay OE has now picked up, relays 0K3and 0K4 in the same manner that relays OKI and 0K2 were picked up at theconclusion of the first digit. In the case illustrated, when relay OD5becomes energized during the third digit, current flows from terminal X,over front contact 35 of relay 32, wire 31, arm 13 of finder F, wires 82and 83, back contact 84 of relay 0K6, wire 85, front contact 86 of relay0K4, Wire 81, front contact 88 of relay 0K2, wire 89, front contact 98of relay ODS, and thence through winding of relay OE to terminal Y.Relay OE sticks up, and serves to introduce the pause between the thirdand fourth digits. It should be noted that "with this arrangement thethird digit contains three units. Furthermore, "the energization ofrelay OE to introduce the pause at the end of the third digit picks uprelay 7 tact 59 of relay 0K2, wire 60, front contact B l of relay OD3,Wires 62 and 63, the winding of relay OE to terminal Y. When thiscircuit is closed, relay OE becomes energized. Furthermore, the closingof front contact 61 of relay O-E completes a circuit from terminal X,over front contact '61,-

of relay OE wire 68,front contact l0l of relay 0K6, and wire I02 to armHi to finder F, and thence through wire I03 and winding of stop relayOGZ to terminal Y. Relay 0G2 therefore berelay 0H2 drops, magnet ll! offinder F is deenergized and spring 26 restores the armature 25 to theposition shown in the drawings, whereupon each of the arms of the finderF are advanced one step-to brake the contacts which they previouslyclosed. At the same time, relay 32 is de-energized to disconnectterminal X from wire 31. All of the digit relays OK therefore becomede-energized and relay OS also becomes de-energized. Back contact 6 ofrelay OS closes the circuit for relay-1 0A so that relay OA picks up toremain energized until the next code is transmitted. Back contact 3 ofrelay OS closes to restore the normal line circuit, and back contact 1of relay OS completes a circuit for relay CC to hold this relayenergized after relay OA becomes energized. Since relay 00 now remainssteadily energized all of the unit relays return to their de-energizedconditions and the apparatus is therefore restored to normal.

In the foregoing, it has been assumed that there are no further codes tobe transmitted at the time; so that the finder switch will advance onestep and then remain in the position corresponding to code 2133. It willbe noted, however, that contact 20 of relay 0H2 is connected in multiplewith the corresponding contacts of all other OH relays, so that if anyof these relays have been energized the supply of current to steppingmagnet ID will not be discontinued when relay 0H2 releases. Contact 33of relay 0H2, however, controls a circuit that is individual for thisrelay and therefore when 0H2 releases, relay 32 will become deenergizedand close its back contact 3|, and if current is then supplied to magnetI0, relay 23 will become energized to initiate the stepping action offinder F as already described so that the finder arms will be steppedaround until arm l5 reaches a position to close a circuit over a frontcontact, such as 33, of one of the succeeding OH relays, to again pickup relays 32 and OS to transmit the code which corresponds to theposition finder F then occupies.

It has already been pointed out that when lever to is moved to itsreverse position, the line is supplied With the code 2132. It will beobvious, however, from an examination of the drawings that if the leverw is moved to its normal position, the operation of the apparatus issimilar to that just described, but the code delivered to the line willthen be 2131, the difference in the last digit being comes energized tode-energize relay 0H2. When supplied to the line circuit in the mannerjust described operate the line relays at each station accomplished bythe selection of contacts on the finder F and the consequent change inthe control circuits for transfer relay OE. In similar manner, when theleft-hand contact of lever 1' is closed, the code delivered to the lineis 2133, when-the middle contact of this lever is closed, the code is2134, and when the right-hand contact lever r is closed, the code 21-35is delivered to the line. These particular codes have been chosen by wayof illu- -tration only, and it should be understood that any other fourdigit codes could beproduced depending .upon the connections of thefinder contacts with the bus bars which connect with the contacts of thedigit relays OK.

As has been mentioned hereinbefore, thecodes in synchronism with theline relay' OL at the office. The line relay at each station controlsapparatus which is selectively responsive to the code delivered to theline circuit from the ofiice. Referring now to Figs. 3 and '4, it willbe seen that the line relay IL is normally included in the seriescircuit including line wires I and 2, this circuit passing from linewire 2 extending to the oifioe, through front contact I04 of relay IC,winding of relay IL, contact I05 operated by relay IS, and thencethrough'line wire 2 to the apparatus at the next station, and so onthrough each station in turn, the line circuit being completed byconnectingthe outgoing portions of line wires I and 2 together at themost remote station. The station equipment, in addition to the relaysalready mentioned, includes two slow acting relays IB and IJ and alsoincludes a series of unit relays D and digit relays K.

The apparatus at the station which is selectively responsive to thecodes received from the office may be utilized to control governingmeans of any suitable form. For purposes. of illustration, I have showna section of railway track a-b connected with a siding 2 by a switch I96of the usual and well known form. A track relay IR. is connected withthe rails adjacent one end of section ab and a battery 229 is connectedacross the rails adjacent the other end of the section. Track relay IRis therefore energized under normal conditions but is de-energized when'a train occupies section ab. The switch I is driven by a motor IM whichin the form here Jshown comprises an armature H2 and a field III. Whenswitch I06 occupies its normal position, in which itis illustrated inthe drawings, cont-acts Nil-Alli Ii0-Iil8 and I09-I09 are closed. Whenthe switch occupies its reverse position, however, the contacts justmentioned, are open, and contacts I0'iI0l I08-I00 and II'I9---I0El areclosed. The switch also'controls a contact IIEiI I0 which is closedat'all times except when the switch occupies its reverse position and acontact HEB-Hu which is closed at all times except when the switchoccupies its normal position. The motor IlVf is controlled by two switchcontrol relays IP and IQ as will be described in detail hereinafter.

;for example, I will assume that the line is bein supplied with code2132 as was previously described in connection with the operation of theapparatus located at the ofiice. The first opening of the line duringthe long time interval required for relay CA at the ofiice to close itsback contacts, deenergizes relay IL at the station, thereby energizingthe first unit relay IDI over back contact I I3 of relay IL. The nexttime relay IL becomes energized, relay IDZ becomes energized over frontcontact I I3 of relay IL and front contact II4 of relay IDI. When relayID2 picks up, current flows from terminal 11:, over front contact IIB ofrelay ID2, wires III and IIO,winding of relay IJ to terminal 1;. RelayIJ is therefore energized as soon as relay ID2 becomes energized, anddue to its slow releasing characteristics, relay IJ remains energizedduring the pauses between digits in a code, at which times relay ID2 isde-energized. When relay IL next becomes de-energized, relay ID3 picksup over front contact. II of relay ID2, but relay ID3 is subsequentlyheld up by current supplied thereto over front contact H0 of relay ID2,and front contact II9 of relay ID3. Relay IL then again becomesenergized at the conclusion of the second unit of the first digit in thecode now being supplied to the line, and then there is a pause beforethe next operation of relay IL. The energization of relay IL picks uprelay ID4 and this relay is subsequently stuck up over front contact iit of relay ID2. During the pause between digits, after a time interval,relay IDI releases, thereby opening, at front contact II I thereon, thecircuit for relay ID2. Relay ID2 therefore drops, opening the circuitsfor all unit relays D below it because the stick circuits for all theseunit relays include a front contact II6 of relay IDZ. But during thebrief interval after the deenergization of relay IDI and prior to theopening of the front contacts of relay ID2 a circuit is established fordigit relay IKI, current flowing from terminal :12, over front contact Iof relay IJ, wires I2I, I38 and I22, back contact I23 of relay IDI, wireI24, front contact I25 of relay 'ID2, wire I26, front contact I21 ofrelay ID3, wire I28, back contact I29 of relay ID5, wires I30,

I31 and I32, back contact I33 of relay IK2, wire I36, and winding ofrelay IKI to terminal :1]. Relay IKI therefore becomes energized, but assoon as relay ID2 releases, the circuit for relay IKI is opened. Thisrelay is slow releasing, however, and prior to the opening of its frontcontacts, relay ID2 closes its back contact I25 and current then flowsfrom terminal 1:, over front contact I20 of relay IJ, wires I2l and I22,back contact I23 of relay IDI, wire I24, back contact I25 of relay ID2,wires I35 and I36, front contact I3'I of relay IKI, and winding of relayIK2 to terminal y. Relay IK2 therefore becomes energized and issubsequently stuck up over a circuit from terminal 1:, through frontcontact I20 of relay IJ, wires I2I and I39, front contact I20 of relayIK2 and winding of relay IK2 to terminal y. At the conclusion of thepause between the first'and second digits, the relay IL again commencesto operate and during the second digit the unit relays D are energizedin succession in the same manner'as has already been described. Thesecond digit in the code now being delivered to the line consists of asingle impulse, however, so that after relay IL has once becomede-energized and again picks up, another pause occurs between the secondand third digits. The de-energization of relay IL picked up relay IDIand the next energization of iii) relay IL picked up relay ID2. Duringthe pause between the second and third digits, relay IDI drops andcurrent then is supplied to relay IK3 over a circuit which may be tracedfrom terminal a: over front contact I20 of relay IJ, wires I2I and I22,back contact I23 of relay IDI, wire I24, front contact I of relay ID2,wire I26, back contact I21 of relay ID3, wires I4I, I42, and I43, frontcontact I44 of relay IK2, wire I45, back contact I46 of relay IK4, wireI41, and winding of relay IK3 to terminal y. After relay IK3 has pickedup, relay IK4 is energized as soon as relay ID2 opens, and relay IK4 issubsequently stuck up over its own front contact I49 and front contactI20 of relay IJ, relay IK3 again becoming de-energized. In similarmanner, during the pause at the end of the third digit, since all of theunit relays up to and including relay ID6 are now energized, due to thethree units in the third digit, a circuit is completed for relay IKE assoon as relay IDI drops. This circuit may be traced from terminal as,over front contact I20 of relay IJ, wires I2I and I22, back contact I23of relay IDI, wire I24, front contact I25 of relay ID2,'wire I26, frontcontact I21 of relay ID3, wire I28, front contact I29 of relay ID5, wireI50, back contact I 5I of relay ID1, wires I52 and I53, front contactI54 of relay IK4,-wire I55, back contact I56 of relay I K6, wire I51,and winding of relay IK5 to terminal 1/. When relay ID2 becomesde-energized relay IK6 picks up over front contact I58 of relay IK4 andis thereafter stuck up over its own front contact I59 and front contactI20 of relay IJ. Furthermore, the closing of front contact I62 of relayIK6 completes a circuit for relay IK1, over which current flows fromterminal at, over back contact I60 of relay IS, wire I6I, frontcontactI62 of relay IK6, and winding of relay IK1 to terminal y. With relay IK1 energized, an impulse is delivered over one of the front contacts ofthis relay at the conclusion of the fourth digit. I have assumed thatthe code being delivered is 2132 and hence when relay IDI drops afterthe conclusion of the fourth digit, current flows from terminal :0, overfront contact I20 of relay IJ, wires I2I and I22, back contact I23 ofrelay IDI, wire I24, front contact I25 of relay ID2, wire I26, frontcontact I21 of relay ID3, wire I28, back contact I29 of relay ID5, wiresI30, I63 and I64, front contact I65 of relay IK1, wire I66, winding ofrelay IQ to terminal y. Since the code has now been completed, relay ILremains energized and all of the unit relays become de-energized. At theconclusion of the retardation period of relay IJ, this relay releasesand breaks the circuit for digit relays IK2, IK4 and IK6. These relaystherefore become de-energized and relay IK1 also becomes ole-energizedto restore the apparatus shown on Fig. 3 to its normal condition. Theimpulse delivered to relay IQ, as described above, energizes this relay,thereby interrupting the stick circuit for relay IP and allowing relayIP to become de-energized. Relay IQ is maintained in its energizedcondition after the opening of relay IK1 by current which flows fromterminal .23, over back contact I61 of relay IP, front contact I68 ofrelay IQ, and a winding of relay IQ to terminal y. When. relay IQbecomes energized, a circuit is closed for motor IM, operating switchI06, this circuit passing from terminal at, over front contact I69 oftrack relay IR, wires I10 and Ill, front contact I12 of relay IQ, wireI13, armature II2 of motor IM, wire I14, back contact I15 of relay IP,wire I16, front contact I11 of relay IQ, wire I18, contact 0-- H0operated by switch I06, and field III of motor IM to terminal y. Themotor IM is therefore energized to drive the switch I66 to its reverseposition. When the switch has attained its full reverse position,contact IIOI I0 opens to de-energize the motor. It should be observedthat if the operator at the control office wishes to restore the switchto its normal position, he may do so by restoring lever w at the ofiiceto its normal position, whereupon code 2131 will be delivered to theline and this code will cause operation of relay IP at the station.Relay IQ will then be ole-energized and relay IP will be stuck up tocomplete a circuit for motor IM by means of which the motor will beenergized to restore the switch to its normal position in which it isillustrated in the drawings.

In discussing the control of the signals t, u and c, it should be notedthat as shown in the drawings, relay IT is energized, by currentsupplied thereto over back contact I61 of relay IV, back contact I89 ofrelay IU, and front contact I88 of relay IT. When relay IT is energized,current is supplied to the upper blade of signal if or to the lowerblade of this signal according as switch I06 ocupies its normal orreverse position. For example, as shown in the drawings, the switch isnormal and relay IT is energized, and under these conditions, currentflows from. terminal 3:, over front contact I69 of relay IR, wires I10and I90, front contact I9I of relay IT, back contact I92 of relay IU,wire I93, contact I01I01 wire I94, and operating mechanism of the upperblade of signal if to terminal y. The remaining signal circuits aresimilar to that just described and will be obvious from the drawingswithout tracing them in detail. It should be observed, however, thatwhen relay IU is energized, signal 1: or signal a is cleared dependingupon the position of the switch I06. If code 2133 is delivered to thestation shown in Figs. 3 and 4, relay IT becomes energized and if code2135 is delivered to this station, relay IU becomes energized. If,however, code 2134 is supplied to the line, the trip relay IV becomesenergized, thereby interrupting the stick circuit for which ever one ofrelays IT or IU is energized, thereby releasing these relays and causingall signals to indicate stop.

It is to be noted that the station apparatus of Figs. 3 and 4 mayreadily be arranged to receive any of the different stationcode-combinations which my system employs, byconnecting relays IKI, IK3and IK5 to the group of five vertical bus wires I42, I31, etc.,according to the code desired which of course is the same as that of theoffice finder switch for the position associated with the station inquestion. When the station code connections are arranged as in Fig. 3,it is evident that the station apparatus will fully receive only thosecodes in which the first three digits are 213, and that when other codesare received, relay IK1 will not become energized.

As has been suggested hereinbefore, the equipment illustrated on Figs. 3and 4 is arranged to permit the transmission of codes to the linecircuit for the purpose of actuating indication means in the controloflice to inform the operator concerning the condition of trafficgoverning devices located at the station. For purposes of illustration Ihave arranged the apparatus to give indications in the officeconcerningthe condition of the track section a-b and also concerning the positionof the switch I06.

In explaining this feature of my invention, I

will first assume that the track relay IR becomes cle-energized as bythe entrance of a train into section ab. When this occurs, back contact2M of relay IR closes and current flows from terminal :0, through backcontact 20I of relay IR, wire 202, back contact 223 of relay IG2, wire2B4, winding of relay IH2, wires 205 and 206, back contact 2!]? of relayIll-I3, wire 208, back contact 239 of relay IH4, wire 2 II], winding ofmaster .relay IS at the top of Fig. 3, wire 2! I, back contact 2I2 ofrelay IJ, wire 2I3, and back contact 2I4 of relay IDI to terminal y. Theresult of deenergizing relay IR. is thus to pick up relay IS, but if theline is in use, this will not occur until the line becomes availablebecause the pickup circuit for relay IS includes back contacts of theslow release relays IDI and IJ controlled by line relay IL. When ISpicks up, contact I8! is opened, and front contact 2I'I of relay IS isclosed. The opening of contact I05 disconnects that portion of the linewire 2 beyond the station and the closing of contact 2I'I of relay ISconnects the portion of the right-hand terminal of line relay ILdirectly with line wire I so that the line circuit including the officeand the station which is about to transmit a code is completed. Theclosing of front contact 2I8 of relay IS completes a circuit for relayIB from terminal 1c, over front contact 2I8 of relay IS, winding ofrelay IB, front contact 2I9 of relay IC, wire 22!], back contact 22I ofrelay IKI, wire 222, back contact 223 of relay IK3, wire 224, backcontact 225 of relay IK5, wire 226, and back contact 221 of relay IKB toterminal Relay IB thereupon becomes energized and interrupts, at backcontact 228 thereon, the circuit for the transmitter relay IC, whichlatter relay then becomes deenergized and opens at front contact 2 I 9thereon, the circuit just traced for relay IB. The opening of relay ICalso opens the normally closed line circuit to the dispatchers office atfront contact I04. When relay IC becomes de-energized, relay'IB alsobecomes de-energized, thereby again closing the circuit for relay ICwhich then becomes energized to pick up relay IB and close the line. Itfollows therefore that relays IB and IC operate to alternately open andclose the line and by properly grouping the, impulses thus supplied tothe line, indication codes may be obtained of the type to which theapparatus in Figs. 5 and 6 is responsive. The intermittent energizationof relay IL picks up the unit relays D'in succession, in the same manneras described in connection with the reception of codes at the station.It should be noticed that when relay ID2 becomes energized, a circuit isclosed for relay IJ and that due to the slow acting characteristics ofthis relay, its front contacts are maintained closed during theintervals that relay ID2 is de-energized between digits. When relay IJpicks up, wire 2! I is disconnected from wire 2I3 and is connected overfront contact 2I2, wire 2I5, and front contact ZIfi of relay IS directlywith terminal y, thereby completing a stick circuit for relay IS. Whenrelay IDI picked up due to the opening of the line circuit, the circuitof relay IS was opened at back contact 2M. Since relay iS is a slowrelease relay, it remains picked up for the relatively short intervalthat the line is opened by the operation of relays IB and IC, and assoon as the line is closed and relay IJ picks up, relay IS becomesenergized over its stick circuit as just described, and remainsenergized until relay IJ drops at the end of the code. The operation ofrelays IB and IC continues, thereby intermittently operating relay IL,and when relays IC and IL release the second time, relay ID3 picks up.When this occurs current flows from terminal a), over front contact I60of relay IS, wire 229, front contact 230 of relay IDI, wires 23I andI26, front contact IZI of relay ID3, wire I23, back contact I29 of relayID5, wires I30, I3I and I32, back contact'I33 of relay IK2, wire I34,and winding of relay IKI to terminal t so that then relay IKi becomesenergized. When relay IB releases, relay IC picks up and closes theline, thereby-energizing relay IL. A pause now occurs, because thecircuit of relay IB is open at back contact 22I of relay IKI, so thatrelay IB remains released. and relay 'IC is held energized. After a timeinterval, relay IDI drops, openin onebranch of the circuit for relay IKIjust traced, but'relay IK is now energized over another branch of thiscircuit which includes front contact I20 of relay IJ,back contact I23 ofrelay IDI and front contact I25 of relay ID2. Relay iD2 now releases,and when relay ID2 opens its front contact IIB, relays ID3 and ID4become tie-energized and the closing of back contact I25 of relay IDZalso completes a pick-up circuit for relay IK2 over front contact I3'Iof relay IKI which pick-up circuit is similar to the circuit previouslytraced for this relay during the explanation of the operation of theapparatus when a code is being received. Relay IK2 is subsequent- 1ystuck upover its own front contact I40 and front contact I20 of relayIJ, but it should be noted that when the circuit for relay IK2 isclosed, the; circuit for relay IKI is opened at front contact I 25 ofrelay ID2 and after relay IK2 picks up it is maintained open at backcontact I33 of relay IK2. It follows that relays IKI becomesde-energized when relays IK2 is picked up. After the time intervalrequired for relay I KI to drop, the circuit is re-established for relayIB, which thereupon becomesenergized and again commences to causeperiodic operations of relay IC. In similar manner, during the seconddigit, relay IE3 picks up to hold the circuit for relay IB open at itsback contact 223, when relay IDI becomes de-energized. The circuit forrelay IK3 passes from terminal at, over front contact 56B of relay IS,wire 229, front contact 230 of relay IDI, wires 23I and I26, backcontact I2'I of relay ID3, wires I4I, I42 and I43, front contact I44 ofrelay IK2, wire I45, back contact I46 of relay IK I, wire I41 andwinding of relay IK3 to terminal After relay IK3 is energized, relay IKQis first picked up and then stuck up and relay IKS releases to set relayIB into operation to deliver, the third digit. It should be noted thatbetween the beginning and end of the last impulse of a digit, there isinterposed the release period of relay IDI, plus the release period ofrelay ID2, plus the release period of one of the slow acting relays Kand the parts may be so proportioned that the pause thus introduced intothe code has the desired time characteristics. At the conclusion of thethird digit of the code, relay IK5 picks up and relay IKE subsequentlybecomes energized and is then stuck up over its own front contact I59and front contact I20 of relay IJ.

Now if the last digit contains the proper number of units or impulses,an impulse will be delivered at the end of such digit, to pick up relayIK8. In the present description I have assumed that relay IHZ has beenenergized to deliver code 2132. During the last digit then, after theline relay IL has been operated to supply two impulses to the line,current flows from terminal :1: over front contact I60 of relay IS, wire229, front contact 233 of relay IDI, wires 23I and I26, front contact I21 of relay ID3, wire I28, back contact I29 of relay ID5, wires I38,I63, 232 and 233, front contact 234 of relay IH2, wires 235 and 235,front contact 231 of relay IKE, wire 238, winding of relay I K8 toterminal y. Relay IK8 therefore becomes energized and opens, at backcontact 221 thereon, the circuit for relay IB. Relay IK8 remains stuckup over its own front contact 239 and front contact I20 of relay IJ. Butthe energization of relay IKB also energizes stop relay I G2, currentfiowing from terminal at, over front contact 240 of relay I K8, wires MIand 242, front contact 243 of relay IH2, wire 244, and winding of relayIGZ. After relay I G2 has become energized, it is stuck up over backcontact 20I of relay IR and itsown front contact 283. But the opening ofback contact 203 of relay IG2 interrupts the circuit for relay IH2 andfor relay IS, so that both of these relays become deenergized. Theopening of relay IS restores the line circuit by closing contact I85.Relay IB is now held open, and relay IC is continuously energized overback contact 228 of relay IB. Relay IL is therefore continuouslyenergized and all of the unit relays D become de-energized. After a timeinterval, relay IJ opens, to open the stick circuits for relays IK2,IK4, IK6 and IK8, whereupon these relays open and restore the apparatusto its normal condition. It should be pointed out that if relay IRbecomes energized, the operation of the apparatus will be similar tothat just described with the exception that since front contact 245 ofrelay IHI would then be closed, the last digit of the code then suppliedto the line would be a single impulse. In similar manner, if the switchIE6 is moved to its reverse position, so that contact Ill9-I09 isclosed, relay I H4 is energized in series with the relay IS, and thecode then supplied to the line is 2134. Finally, if the switch isrestored to its normal condition to close contact ID9I89 theenergization of relay IH3 in series with relay IS initiates an operationof the equipment which delivers code 2133 to the line. It will benoticed that the circuits for start relays IHI and IH2 are carried overback contacts on the start relays IH3 and IE4 so that if either of thetwo latter relays is energized, as would be the case when a codecorresponding to one of these relays is being delivered to the line, andthe condition of track relay IR then changes, neither relay IHI nor IH2can pick up until both relays IH3 and IH4 have returned to theirdeenergized condition. It is also to be noted that since those portionsof the circuits of relays IKI, IK3 and IK5 which determine thecodecombination for the station are employed in both sending andreceiving, the first three digits of each indication code sent by astation are the same as the first three digits of the control codeswhich the station receives, the combination being 2I3 in the exampledescribed, as already pointed out.

Referring now to Figs. 5 and 6, these views show a line relay OL whichwas discussed in connection with Figs. 1 and 2. Relay OS is also shownon Fig. 5. The line relay 0L, which is periodically energized andde-energized when a code is being received at the control office,operates a series of unit relays each designated by the referencecharacter d with a prefix O and a distinguishing suffix. Associated withthese unit relays is a series of digit relays each designated by thereference character It with a suitable prefix and suflix, and aplurality of series of register relays e, f and g. The relay OJ iscontrolled by the second unit relay OdZ in the same manner that relay IJis controlled by relay ID2 in Fig. 3.

Alternate energization or de-energization of the line relay OL picks upthe unit relays d in succession. When the firstdigit has been received,energy is supplied to one of a group of five wires 7', depending uponthe number of impulses in this first digit. Assuming that the code 2132is being received, as when a train enters the section a--b in Fig. 4,the first digit of the code comprises two impulses so that afterthis-digit has been received, relays OoZI, OdZ, Od3 and OM areenergized. Relay OJ is energized over front contact 254 of relay 0512.During the pause following the reception of the first digit, relay 0Lbecomes energized. Relay Odl first opens, thereby de-energizing relay0112. During the brief interval that relay Od2 remains energized due toits slow releasing characteristics, current flows from terminal X, overfront contact 258 of relay OJ, wire 25?, front contact 258 of relay Od2,wires 253, 268 and 285, back contact 282 of relay OdI, Wire 263, frontcontact 264 .of relay 0033, wire 265, back contact 267 of relay 0:25,wire 268, back contact 289 of relay Ok2, wire 278, and winding of relaye2 to terminal Y. When relay 62 becomes energized, it is held in thiscondition over its own front contact Z'II and front contact 256 of relayOJ. At the same time that current is supplied to a selected one of agroup of wires to pick up a selected one of the group of relays e,current flows from terminal X, over front contact 253 of relay OJ, wire251, front contact 258 of relay 0112, wires 2% and 212, winding of relayOkI to terminal Y. Relay OkI having thus been energized, is stuck upover its own front contact H3 and front contact 258 of relay OJ. Whenrelay Od2 finally drops during the. pause at the end of the first digit,current flows from terminal X, over front contact 253 of relay OJ, wire251, back contact 258 of relay Od2, wires 21 and 215, front contact 276of relay OM and winding of relay GM to terminal Y. Relay 0702 thereforebecomes energized and is subsequently stuck up over its own frontcontact 3 and front contact 255 of relay OJ. When the second digit ofthe code is received by line relay 0L, the unit relays 0d are,successively energized as before, but at the conclusion of this digit,an impulse of energy is supplied to a selected one of a group of Wiresm, depending upon the number of impulses at the conclusion of the secondimpulse, after relay OdI has released and while relay 0012 is stillpicked up, current flows from terminal X over front contact 256 of relayOJ, wire 251, front contact 258 of relay 0012, wires 259, 260 and ZBI,back contact 262 of relay OdI, wire 263, back contact 26d of relay 0(13,wire 219,.

front contact 2% of relay Olc2, wire 28L back contact 282 of relay OM,wire 283 of group m, and winding of relay fl to terminal Y. Relay fltherefore becomes energized and is subsequently stuck up over its ownfront contact 284 and front contact 256 of relay OJ. It will thereforebe seen. that at the conclusion of the second digit, one of the relays fis energized, depending upon the number of impulses in such digit.

Relays CR3 and 07rd become energized during in such digit. Thus with thecode 2132,

and OM. At the conclusion of the third digit, an impulse of energy issupplied to a selected one of 'a'group of wires n for picking up aselected one of a group of relays 9, depending upon the number ofimpulses in such digit. Since the code now being received has threeimpulses in its third digit, when relay Odl drops at the conclusion ofthe third digit, current flows from terminal X, over front contact 256of relay OJ, wire 251, front contact 258 of relay 0e12, wires 259, 260and 26I, back contact 262 of relay OdI, wire 263, front contact 264 ofrelay Od3, wire 265, front contact 261 of relay Od5, wire 288, backcontact 289 of relay Od1, wire 290, front contact 29I of relay Ok2, wire292, front contact 293 of relay OM, wire 294, back contact 295 of relayOk6, wire 296 of group n, and winding of relay g3 to terminal Y. Relay93 therefore becomes energized and is held in this condition by virtueof a stick circuit including its own front contact 291 and front contact256 of relay OJ.

During the pause at the end of the third digit relays O7c5 and 0706become energized, so that at the conclusion of the fourth digit, animpulse of energy is delivered to a selected one of a group of wires 1)depending upon the number of impulses in such fourth digit. The threegroups of relays e, J, and 9, corresponding to the first three digits ofeach code, control a series of relays each designated by the referencecharacter h with a distinguishing suflix. The relays h are so controlledthat for each possible combination of the relays of the first threegroups e, I and 9!, one of the relays h will be energized and in thepresent instance since the first digit was 2, relay 62 is energized,since the second digit was a 1, the relay fl is energized, and since thethird digit was a 3, relay 93 is energized. It will be plain that withthese three relays energized, a circuit is completed from terminal X,over front contact 211'of relay e2, wire 218, front contact 285 of relayfl, Wires 286 and 281, front contact 298 of relay 93, wire 299, windingof relay h52 to terminal Y. Each of the relays h has two pair ofcontacts which are separately connected in multiple with four of thefive wires of the group p, and each pair of contacts controls apolarized indication relay designated by the reference character i witha distinguishing suffix.

At the conclusion of the fourth digit then, after relay OdI releases,current flows from terminal X, over front contact 256 of relay OJ, wire251,

front contact 258 of relay Od2, wires 259, 260

and 26I, back contact 262 of relay OdI, wire 263, front contact 264 ofrelay Od3, wire 265, back contact 261 of relay Od5, wire 268, frontcontact 269 of relay Ok2,wire 3I3, front contact 300 of relay OM, wire30I, front contact 302 of relay 0706, wire 304 of group N, thencethrough wire 305 to front contact 306 of relay h52, Wire 301, winding ofrelay 1106 to terminal Y. The circuit is closed for only a briefinterval, during which the armature of relay 2106 is swung to the right,lighting lamp 308 to indicate to the dispatcher that the section abshown in Fig. 4 is occupied by a train. Each of the relays i is arrangedto maintain its contacts in the position to which they were last movedso that with the indications obtained by energizing these relays in onedirection or the other persists after the energizing circuits for therelays have been opened. After a code has been received, all of the unitrelays d become de-energized and relay OJ also becomes de-e'nergized.When front contact 256 of relay OJ opens, all of the digit relays kbecome deenergized and whichever ones of relays e, f, g and h are closedalso become de-energized. The apparatus is therefore restored to itsnormal condition in which it is illustrated in the drawings, except thatthe indication relays 2' remain in the positions corresponding to thelast indication code received.

Attention should be drawn to the fact that had the final digit of thecode been 1, instead of 2, energy would have been connected with theother winding of relay H06 over front contact 3 I4 of relay M2 at theconclusion of the code, and under these conditions lamp 308 would beextinguished. In similar manner, the indication relay iI01 is arrangedto indicate to the operator the position of the switch, lamp 309 beingenergized to indicate that the switch is normal when relay 2'I01 isenergized in one direction, and lamp 3I0 being lighted to indicate thatthe switch is reversed when the relay 81' is energized in the oppositedirection.

I have described my invention as applied to the control of switches andsignals and the return indication of track circuits and switches butthis particular arrangement is not essential and has been disclosedsolely for purpose of illustration. It should be noted that at theoffice, the unit relays of the receiving equipment, Fig. 5, arecontrolled over back contact 249 of relay OS, but as has already beendescribed, relay OS is energized when the ofiice equipment is sending acode. When a code is being received at the office, relays OJ and OdI areenergized, but back contacts of these two relays are included in serieswith the operating circuit for relay OS which must be energized beforethe sending equipment at the oflice shown on Figs. 1 and 2 can be setinto operation. It follows that when the ofiice is sending, thereceiving equipment at the office is disconnected,'and contacts 38 and39 in the circuit of relayv OS are prevented from opening. Converselywhen a code is being received at the office the sending equipment isdisconnected.

Furthermore, at the station (Figs. 3 and 4) relay IS must be energizedin order to send a code to the ofiice. But a control can be received atthe station only when relay IS is de-energized to close back contact I60for energizing relay Ikl during the last digit of the code. It followsthat the sending and receiving equipment at the station cannotinterfere.

Moreover, even if two stations start sending at the same time, nointerference will occur, because the more remote station will be lockedout until the station near the office completes its code, by theoperation of contact I05 of relay IS. If the ofiice and a station startsending at the same time, the ofiice will take precedence for thefollowing reason: When the line is opened at the office to start acontrol code, it is held open for a relatively long interval by relayCA, as already described. When the line is opened at a station to startan indication code, the periodic operation of relays IB and IC begins atonce so the first opening of the line is relatively short. During thisinterval the pickup circuit of relay IS is open, but its stick circuitis not available until the line becomes closed, and relay IS, being aslow release relay, remains picked up if the interval is relativelyshort, but releases if it is relatively long, as would be the case ifthe oflice and station start sending at the same time. In that case,relay IS becomes released and the station apparatus is then in conditionto receive the control code and the normal line circuit is also restoredso that the code can be received by a more remote station. It follows,therefore, that the station equipments can not interfere with oneanother nor with the oflice transmitter.

Although I have herein shown and described only one form of. railwaytraffic controlling apparatus embodying my invention, it is understoodthat various changes and modifications may be made therein within thescope of the ap ended claims without departing from the spirit and scopeof my invention.

Having thus described my invention, what I claim is:

1. Railway traffic controlling apparatus comprising a normally closedline circuit including a source of energy, and a normally closedcontact, means for at times periodically opening said contact, a seriesof relays arranged to be operated in succession when said contact isperiodically opened and closed, a trafiic governing device, means forstopping operation of said contact in response to the energization of aselected one of said relays, means depending upon the condition of saiddevice for determining which one of said relays is to be selected tostop the operation of said contact, and means controlled by said circuitand selectively responsive to periodic interruptions thereof.

2. Railway trafiic controlling apparatus comprising a normally closedline circuit including a source of energy, and a normally closedcontact, means for at times periodically opening said contact, a seriesof unit relays arranged to be 010- erated in succession when saidcontact is periodically opened and closed, a transfer relay, 2, seriesof digit relays controlled by said transfer relay, a traffic governingdevice means for controlling said transfer relay in response to theenergization of a selected one of said unit relays, means controlled inaccordance with the condition of said digit relays and the condition ofsaid device for determining which one of said unit relays is to controlsaid transfer relay, and means controlled by the last digit relay insaid series for stopping operation of said contact.

3. Railway traflic controlling apparatus comprising a normally closedline circuit including a source of energy, and a normally closedcontact, a series of unit relays controlled in cascade, a series ofdigit relays controlled in cascade, and controlled by said unit anddigit relays for at times periodically opening said contact to supplysaid circuit with different codes each having a plurality of groups ofenergy impulses separated by time intervals.

i. In combination, a line relay, means for at times supplying said relaywith diiferent codes each having a plurality of digits, a series of unitrelays controlled by said line relay and arranged to be operated insuccession by successive imin each digit of said codes, a plurality ofdigit relays arranged to become operated progressively said digits arereceived by said line relay, a plurality of series of register relays,means controlled by certain of said digit relays for operating aselected one in each series of register relays depending upon the numberof units in the corresponding digit of said code, and means controlledby said register relays and selectively responsive to said codes.

5. In combination, a line relay, means for operating said relayintermittently in accordance with a code madeup of a plurality of digitseach comprising one or more units, a series of unit relays, meanscontrolled by said line relay for energizing said unit relayssuccessively during each said digit, a series of digit relays, means forenergizing said. digit relays successively in re sponse to successivedigits of said code, and means controlled by said digit relays andselectively responsive to said code.

6. In combination with a line circuit including a transmitting contact,a start relay, a stop relay, means effective only when said stop relayis deenergized for at times energizing said start relay, means effectivewhen said start relay is energized for intermittently operating saidtransmitting contact to deliver a code to said line circuit, a series ofunit relays controlled over said line circuit and arranged to beenergized successively in response to intermittent operation of saidtransmitting contact, means controlled by said unit relays for at timestemporarily stopping said transmitting contact to produce a. pausebetweeen impulses in the code, and means controlled by said unit relaysand eifective at the conclusion of said code to energize said step relayto thereby release said start relay.

7. In combination, a line relay, means for operating said line relay inaccordance with a code made up of a plurality of digits each having oneor more units, a plurality of groups of relays one group for each digit,means controlled by said line relay for energizing a selected relay ofsaid first group depending upon the number of units in the first digitof said code, means for energizing a selected relay in. each remaininggroup at the conclusion of the corresponding digit depending upon thenumber of units in such corresponding digit, and governing meansselectively controlled by the relays of the group corresponding to thelast digit.

8. In combination, a line circuit including a transmitting contact, aseries of unit relays, means for operating said transmitting contactintermittently to deliver a code to said line circuit, means forenergizing said unit relays successively in response to intermittentoperation of said contact, means controlled by selected ones of saidunit relays for at times stopping said transmitting contact temporarilyto introduce a p'ausein said code and to de-energize all said unitrelays, and means controlled by said unit relays for permanentlystopping said transmitting contact at the conclusion of a complete code.

9. In combination, a line relay, means for intermittently operating saidline relay in accordance with a code made up of a plurality of digitseach having one or more units, a series of unit relays, means controlledby said line relay for progressively energizing said unit relays inresponse to successive units in a digit whilepermitting all said unitrelays to open at the conclusion of each digit, a series of digitrelays, means for energizing alternate ones of said digit relaysprogressively one at the expiration of a time interval following theconclusion of each digit, and means for energizing the remaining digitrelays each when the preceding digit relay in the series becomesenergized and all said unit relays are open.

10. In combination, a line relay, means for intermittently operatingsaid line relay in accordance with a code made up of a plurality ofdigits each having one or more units, a series of unit relays, meanscontrolled by said line relay for progressively energizing said unitrelays in response to successive units in a digit while permitting allsaid unit relays to open at the conclusion of each digit, a series ofdigit relays, means controlled by a definite one of said unit relays forenergizing alternate ones of said digit relays progressively one uponeach opening of such definite unit relay, means for energizing theremaining digit relays each when the preceding digit relay in the seriesisenergized and all said unit relays are open, and means efiective whenany such remaining digit relay becomes closed for holding such relayclosed until the completion of said code.

11. In combination, a normally energized line relay, means forintermittently de-energizing said line relay in accordance with a codemade up of a plurality of digits each having one or more impulses duringwhich the line relay is open and successive digits being separated bytime intervals during which the line relay is closed, a first unit relayarranged to be energized when said I line relay is open and having atime element sufficient to bridge the intervals between successive unitsbut not between successive digits of said code, a second unit relayarranged to be energized when said line relay and said first unit relayare both closed, a plurality of other unit relays controlled by saidline relay and arranged to be energized progressively by impulses afterthe first impulse in each digit, a plurality of digit relays, means forenergizing alternate ones of said digit relays progressively each onewhen a predetermined unit relay becomes energized provided the firstunit relay then opens, and means for energizing the remaining digitrelays each when the preceding relay in the series. is energized and allsaid unit relays are open.

12. In a remote control system, a line circuit, transmitting means fordelivering successive code units to said line circuit, a plurality ofmovable devices, means effective upon a change in the position of any ofsaid devices to initiate operation of said transmitting means, means forat times temporarily stopping said transmitting means to form digits inat least one of which the number of units depends upon which device isoperated and in another of which the number of units depends upon theposition then occupied by the operated device, and means selectivelyresponsive to the number of units in each digit of a code thus suppliedto the line circuit.

13. In a remote control system comprising a line circuit, transmittingmeans for delivering code elements to said line circuit, a series ofunit relays arranged to be operated in succession in response tooperation of said transmitting means but to become deenergized if apause occurs in I the operation of said transmitting means, ap-

paratus for at times causing said transmitting means to pause for abrief instant, a group of digit relays, means for operating said digitrelays successively in response to successive pauses in the operation ofsaid transmitting means, and means for controlling said transmittingmeans by said digit relays.

14. In a remote control system comprising a line circuit, transmittingmeans for delivering code elements to said line circuit, a series ofunit relays arranged to be operated in succession in response tooperation of said transmitting means but to become deenergized if apause occurs in the operation of said transmitting means, a movabledevice, means controlled by said device and by said unit relays for attimes causing said transmitting means to pause for a brief instant, aseries of digit relays, and means selectively responsive to the unitrelays energized at the occurrence of each said pause to operate saiddigit relays successively.

15. In a remote control system comprising a line circuit, a series ofunit relays controlled in cascade, a series of digit relays controlledin cascade and by said unit relays, a different digit relay beingoperated in response to each operation of one or more of said unitrelays, and means controlled by said unit relays and said digit relaysfor at times transmitting to said line circuit a code made up of groupsof energy impulses corresponding to the number of unit relays operatedseparated by time intervals corresponding to the number of digit relaysoperated.

16. In a remote control system comprising an ofiice and a plurality ofstations connected by a line circuit, a single source of energy includedin said line circuit at said office, a'plurality of line relays one atthe oifice and one at each station and all connected in said linecircuit, means at the office for delivering control codes to said linecircuit, means at each station controlled by the associated line relayand selectively responsive to said control codes, means at each stationfor shunting the line at such station through the associated line relayand opening the line to all stations more remote from the ofiice andsubsequently transmitting an indication code to the line circuit betweensuch station and the office, and means at the office controlled by theassociated line relay and selectively responsive to said indicationcode.

17. A remote control system comprising an office and a plurality ofstations connected by a line circuit, a plurality of movable devices ateach of said stations; a control panel for each station all located atthe office and each including a control lever for each device at thecorresponding station, a step-by-step finder switch at said ofiice,means effective when any control lever is actuated to operate saidfinder switch to a selected position, means controlled by said finderswitch when in the selectedposition to transmit a code message over saidline circuit to select the field station associated with the controlpanel containing said levers and to selectively operate the devicecorresponding to said lever to a position in agreement with that of saidlever, and means controlled by the final element of said message to movesaid finder switch to a different position.

18. In combination, a plurality of contacts, a line circuit, a codingunit adapted to transmit to said line circuit a group of code elementsof variable number, means effective when any one of said contacts isoperated to actuate said coding unit repeatedly to transmit a pluralityof groups of code elements, means controlled by said operated contactfor selectively determining the number of code elements in each group toproduce a complete code, and receiving means selectively responsive tosaid complete code.

19. A centralized traffic controlling system for railroads, comprising aplurality of contacts, a line circuit, a plurality of coding units foreach contact each adapted to transmit to said line circuit a distinctivecode element, and means efiective when any one of said contacts isoperated to actuate each of said units in order to.

transmit a complete code to said line circuit.

20. A centralized trafiic controlling system for railroads, comprising aplurality of manually controlled contacts, a stepping contactor, meanseffective when any one of said contacts is operated to advance saidcontactor to a selected position, means effective when said contactoroccupies said selected position to transmit a distinctive code signal tosaid line circuit, and means effective When said code signal iscompleted to advance said contactor to a new position.

21. Code transmitting apparatus comprising a line circuit, a transmitterrelay having a contact in said line circuit, a second relay, a pick-upcircuit for said transmitter relay including a back contact of saidsecond relay, a circuit for said second relay including a front contactof said transmitter relay, said circuits being thereby adapted tocooperate to actuate said transmitter relay repeatedly to produce aseries of impulses in said line circuit, means for energizing saidcircuits to actuate said transmitter, stepping means controlled by saidtransmitter relay and adapted to consecutively close a series ofcontacts, one for each impulse in said line circuit, and meanscontrolled by said last-named means for controlling said transmitter tomodify certain ones of said impulses to produce a code.

22. Remote controlling apparatus comprising a line circuit including aline relay, a transmitter relay for interrupting said line circuit,-asecond relay having a back contact for controlling said transmitter, acircuit for said second relay including a front contact of said linerelay, said lastntientioned circuits cooperating to repeatedly actuatesaid line relay, a series of contacts controlled by said line relay andclosed consecutively when said line relay is repeatedly actuated, andmeans controlled by said contacts for controlling said transmitter tomodify certain. of said impulses to form a code.

23. A code transmitter comprising a line circuit, a line relay in saidcircuit, a transmitter relay having a contact in said line circuit,means for periodically energizing said transrrntter to repeatedlyinterrupt said line circuit to actuate said line relay, a series ofcounting relays energized one at a time in sequence in response torepeated actuation of said line relay, and circuits including contactsof selected ones of said count- I ing relays for stopping saidtransmitter relay for brief inte "vals of time to thereby form a code.

24. A code transmitter comprising a line circuit, a line relay in saidcircuit, a transmitter relay having a contact in said line circuit,means for periodically energizing said transmitter to repeatedlyinterrupt said line circuit to actuate said line relay, a series ofcounting relays energized one at a time in sequence in response torepeated actuation of said line relay, a starting circuit for i1. tiallyenergizing said transmitter relay to start the operation of said codetransmitter, and circuits including contacts of selected ones of saidcounting relays and controlled selectively by said starting circuit forstopping said transmitter to prolong selected ones of its periods ofenergization to thereby form a code.

25. A code transmitter comprising a line circuit, a line relay in saidcircuit, a transmitter rclay having a contact in said line circuit, amaster relay, means for actuating said transmitter relay to interruptsaid line periodically when said master relay is energized, a series ofcontacts closed consecutively by repeated operation of said line relay,a series of register relays, means controlled by the contacts of saidseries and by said register relays for controlling said transmitter toform a code of line signals, means controlled by said code forprogressively actuating said register relays in. accordance with saidcode, and means controlled by the last register relay of said series,

for registering the completion of said code and.

for deenergizing said masterrelay.

26. A code transmitter comprising a line circuit, a line relay in saidcircuit, a transmitter relay for periodically interrupting said circuit,a master relay, means controlled by said master relay for operating saidtransmitter relay, 2. slow release relay controlled by a back contact ofsaid line relay, a second slow release relay controlled by a frontcontact of said line relay, and means controlled by said slow releaserelays to release said master relay to stop: said transmitter wheneither of said slow release relays is released.

27. A code transmitter comprising a line circuit, a line relay in saidcircuit, a transmitter relay for periodically interrupting said circuit,a master relay, means controlled by said master relay for operating saidtransmitter relay, a first slow release relay controlled by a backcontact of said line relay and arranged to release only when said linerelay is steadily energized, a second slow release relay controlled bysaid line relay so as to release only when said line relay is steadilyenergized or deenergized, a pick-up circuit for said master relayincluding back contacts of said first slow release relay, and a holdingcircuit for said master relay including its own front contact and afront contact of said second slow release relay.

28. A code receiver comprising a normally energized line relay, a seriesof contacts closed consecutively by repeated operation of said linerelay in response to a code, a slow release relay controlled by saidline relay and deenergized if said line relay remains picked up orreleased for a period materially longer than the maximum period of anelement of said code, a series of register relays each having a circuitclosed over one of said consecutively operated contacts provided thecorresponding code element is of selected character, and a holdingcircuit for each register relay controlled over a front contact of saidslow release relay.

29. In a remote control system, a line relay, means for deenergizingsaid line relay repeatedly to produce a code, receiving means effectivewhen operated to respond selectively to said code, a first slow releaserelay arranged to be energized when said line relay is deenergized, asecond slow release relay arranged to be energized when said line relayand said first slow release relay are energized, a third slow releaserelay arranged to be energized when said first and second slow releaserelays are energized, means including a back contact of said second slowrelease relay for operating said receiving. means, and means including afront contact of said third slow release relay for maintaining saidreceiving means in operated condition until the code is completed.

30. A code receiver comprising a line relay; a series of counting relayseach except the first controlled over a front contact of a precedingcounting relay, alternate relays being controlled also over the frontcontact, and the remaining relays over the back contact of the linerelay; a series of register relays each provided with a circuitincluding a front contact of a selected counting relay and except incase of the first register relay a front contact of a preceding registerrelay, and a device controlled by the last register relay of the series.

31. A code relay receiver for receiving a code consisting of a pluralityof groups of impulses separated by intervals comprising, a li e relayOperated in accordance with the code, a series of counting relays onefor each impulse and interval of a group, a series of group relays onefor each group, means for operating the series of 1 counting relaysrepeatedly in combination with each group relay in turn, and means forselectively registering each group of code impulses including a contactof a counting relay and a contact of a group relay in series.

32. A code relay receiver for receiving a code consisting of a pluralityof groups of impulses separated by intervals comprising, a line relayoperated in accordance with the code, a series of counting relays onefor each impulse and interval of a group, a series of group relays onefor each group, means for operating the series of counting relaysrepeatedly in combination with each group relay in turn, a series ofregister relays one for each impulse of each group, means forselectively energizing a plurality of register relays over circuitsincluding a contact of a selected counting relay and a contact of eachgroup relay in turn, a plurality of devices, means for selectivelyoperating one of said devices on the last element of a code, said lastmeans including a circuit over closed contacts of each register relay inseries.

33. A code relay receiver for receiving a code consisting of a pluralityof groups of impulses, comprising a line relay operated in accordancewith the code, a series of counting relays controlled by saidllinerelay, a plurality of group relays controlled by said counting relays,means for operating each counting relay a plurality of times each timein combination with a different, group relay, a series of registerrelays for registering the selected impulses of each group whichcomprise the code, and means for selectively operating said registerrelays over circuits including contacts of the group relays to determinethe group and also including contacts of the counting relays todetermine the selected impulse in each group.

34. In a remote control system, station control apparatus comprising aline circuit, a line relay, a series of register relays selectivelycontrolled by said line relay, a movable device, a master relay, atransmitter relay controlled by said master relay, means selectivelycontrolled by said register relays when said line relay is operated by acode signal and said master relay is deenergized to selectively operatesaid device, means controlled by said device when operated to operatesaid master relay and transmitter relay to transmit a code signal tosaid line and thereby actuate said line relay, means controlled by saidregister relays for controlling the transmitter to selectively determinethe code, and means controlled by the final element of said code todeenergize said master relay.

35. \A combined code receiver and transmitter comprising a line relay, aseries ofregister relays selectively controlled by said line relay, anoperating relay, a series of devices to be operated by received codes, amaster relay, a transmitter relay, a release relay, a series of startingcontacts for causing codes to be transmitted, means acting in responseto a received code for maintaining said master relay deenergized, meanscontrolled by said master relay when deenergized and by the finalregister relay of said series to actuate said operating relay, meansacting in response to the closing of one of said starting contacts toenergize said master relay to cause a code to be transmitted, and meanscontrolled by said master relay when energized and by the final registerrelay of said series to actuate said release relay, and means controlledby said release relay to open said closed starting contact and therebyrelease said master relay and stop said transmitter.

36. Code signaling apparatus comprising a code receiver connected to aline circuit at a receiving station and arranged to selectively receivea particular code of signals from said line circuit, a transmitter atsaid station for interrupting said line circuit to transmit a code tothe line to actuate said receiver and to also actuate a distant receiverresponsive to the same code, means controlled by said first namedreceiver for governing said transmitter so as to cause said transmitterto generate the particular code to which said receivers are designed torespond, means contained in said first receiver and operated by thefinal impulse of the code received by said receiver only if saidtransmitter is then ineffective for selectively operating a device atsaid station in accordance with the code, and other means contained insaid receiver and operated by the final impulse of the code received bysaid receiver only if said transmitter is then in operation fordisconnecting said transmitter.

37. A centralized trafiic controlling system for railroads comprising aseries of counting relays interconnected so that they may besuccessively energized, a circuit for the first relay including a backcontact of the second, circuits for the second and each succeeding evennumbered relay each including a front contact of the next precedingrelay of the series, a circuit for the third and each succeeding oddnumbered relay including a front contact of the next preceding relay anda back contact of the next succeeding relay of the series, the circuitsof the odd numbered relays being thereby so arranged that each becomesdeenergized when the next succeeding even numbered relay picks up.

38. A code transmitter comprising means adapted to create a series ofgroups of code elements, means for modifying one element in each groupto form a code, and means controlled by each modified element to preventthe transmission of any additional elements in the same group.

39. A code transmitter comprising means adapted to create a series ofgroups of code elements, means for starting said transmitter to transmita group of elements, means for modifying one element in said group andmeans controlled by said modified element to prevent the transmission ofany additional elements in said group, and to also reset saidtransmitter to its initial condition to start the transmission of asucceeding group of elements.

40. A code transmitter for generating a code consisting of a pluralityof elements of selected character in a line circuit, comprising atransmitter relay for repeatedly interrupting said line circuit, meansfor controlling said transmitter to cause certain elements to be ofselected character and for locking said transmitter to prevent furtheroperation when each of said selected elements is transmitted, linecontrolled means for registering each of said selected code elements,and means controlled by said last named means and efiective when eachselected code element is registered to release said locking means topermit said transmitter to continue its operation.

41. Code transmitting means for delivering successive code elements tothe line wires of a remote control system comprising a transmittingrelay, means for operating said transmitting relay intermittently todeliver code elements to said line wires, selecting means forcontrolling said transmitting relay to impart a selected character tocertain of said elements, code registering apparatus selectivelyresponsive to the character of each code element, and means controlledby said code registering apparatus for permitting the transmitter relayto terminate a code element provided the code element transmittedcorresponds to the condition of said selecting means.

42. Code transmitting means comprising a transmitter for formingconsecutive code elements, means for causing selected code elements tobe of a particular character, line controlled means operated by saidconsecutive code elements, means controlled by said line controlledmeans for registering each code element of selected character, and meansfor holding said transmitter on each code element of selected characteruntil such element is registered by said line controlled means.

43. In combination, a line circuit, a transmitter relay for creating aseries of code elements in said line circuit, a line relay in said linecircuit, a series of contacts arranged to be operated one at a time insequence in response to repeated operations of said line relay, andmeans controlled by said contacts for governing said transmitter relayto control the length of each of said code elements.

is. In a dispatching system, a dispatchers office, a plurality ofstations, circuit selecting means at each station, impulse means in thedispatchers office, a station selecting line circuit, and a series ofimpulse counting relays at each station governed one at a time insequence over said line circuit for operatively connecting said impulsemeans in the dispatchers office with the circuit selecting means at saidstations only one at a time.

45. In a dispatching system, a dispatchers office, a plurality ofstations, selecting means at each station, impulse means in thedispatchers ofiice, station selecting means for automaticallyestablishing an operative connection between said impulse means and saidselecting means at the several stations one at a time in apredetermined. sequence, and a manually operable means in thedispatchers cfiice corresponding with each station for governing theoperation of said station selecting means, whereby the stations may berapidly selected without operating the selecting means except at thestation where said manually operable means has been actuated.

46. In a dispatching system, a dispatchers office, a plurality ofstations, selecting means at each station, impulse means in thedispatchers office, station selecting means in the dispatchers ofliceoperable step-by-step to operatively connect said impulse means to theselecting means at said stations one at a time in turn, means forcausing said station selecting means to advance a step after completionof the operation of the selecting means at the corresponding selectedstation, and manually controllable means for causing said stationselecting means to advance from station to station without operatingsaid selecting means.

47. In a dispatching system for railroads, a dispatchers oifice, aplurality of way stations, a stepping circuit connecting the dispatchersoffice and the several Way stations, manually op-. erable means in thedispatchers oifice for applying to the stepping circuit any one of aplurality of different code combinations of current impulses, a bank ofstepping relays at each station operable sequentially by the impulses ofany of said code combinations, code responsive means at each stationgoverned by said bankof relays and selectively responsive to saiddifferent code combinations, and means for rendering said coderesponsive means at the several stations responsive only one station ata time to the code combination of impulses then being applied to thestepping circuit.

48. A remote control system comprising an office and a plurality ofstations connected by line wires, a movable device at each said station,a control panel for each station all located at the ofiice and eachincluding a control lever for the device at the corresponding station, astep-bystep finder switch at said oflice, means effective to operatesaid finder switch to a selected posi-, tion, means controlled by saidfinder switch to transmit a code message to all said stations to selecta particular field station and to selectively operate the device at suchparticular field station to a position in agreement with thecorresponding lever at the oflice, and means controlled by the finalelement of said message to move said finder switch to a differentposition.

49. In a centralized trafiic controlling system for railroads, a controloffice and a plurality of field stations, a stepping circuit connectingsaid.

control ofiice and said field stations, and step-bystep means at saidcontrol office and at each of said field stations operated insynchronism by time-spaced impulses on said stepping circuitirrespective of their character, said step-by-step means includingstation selecting means responsive only to a particular character ofsaid impulses on said stepping circuit.

50. A selector type system for controlling traffic controlling deviceson a railway comprising, a central ofiice, a way station located at atraffic controlling point along the trackway, a coding circuitconnecting said office and way station, stepping means forintermittently closing said coding circuit to apply impulses to saidcircuit, and a code character determining means which if energizedallows the application of code impulses of one character and ifdeenergized allows the application of code impulses of differentcharacter by said stepping means, said code character determining meansremaining unchanged during the application of a plurality of likesuccessive impulses.

51. A selector type system for controlling traffic controlling deviceson a railway comprising, a central ofiice, a way station located at atrafiic controlling point along the trackway, a coding circuitconnecting said ofiice and way station, stepping means forintermittently closing said coding circuit to apply impulses to saidcircuit, a normally deenergized system starting relay having a frontcontact in said circuit, and a code character determining meanscontrolled by said. starting relay which if in one condition allows theapplication of code impulses of one character and if in anothercondition allows the application of code impulses of a differentcharacter by said stepping means, said code character deermining meansremaining unchanged during the application of a plurality of likesuccessive impulses.

52. In a remote control system of the code type, a starting circuit,means for selectively closing said starting circuit, transmitting meansset into operation when said starting circuit is closed for producingsuccessive code elements, receiving means at a remote point normallyresponding to said code elements, a second receiving means adjacent saidtransmitting means normally responding to said code elements, a stoppingrelay effective when energized to open said starting circuit, and meansoperating upon the termination of a complete code to energize saidstopping relay provided said second receiving means has responded to thelast element of said code.

53. In combination, a control station and a receiving station, a movabledevice and a relay normally occupying positions of agreement, trans,-mitting means at said control station set into operation by a movementof said device out of agreement with said relay for delivering a codemade up of a series of code elements of selected characters to saidreceiving station, means at said control station for registering thecharacters of certain of said elements during the operation of saidtransmitting means, and means controlled by said registering means andeffective upon the completion of said code to operate said relay intoagreement with the new position of said device.

54. In combination, a control station and a. receiving station, amovable device and a relay normally occupying positions of agreement,transmitting means at said control station effective when operated todeliver a code made up of a series of code elements of selectedcharacters to said receiving station, said means including steppingapparatus operated progressively by successive elements of said code,means set into operation by a movement of said device out of agreementwith said relay for operating said transmitting means, means controlledby said stepping apparatus for registering the characters of certain ofsaid code elements at said control station, and means controlled by saidregistering means for operating said relay into agreement with the newposition of said device.

55. In combination, a control station and a receiving station, a movabledevice and a relay normally occupying positions of agreement,transmitting means at said control station effective when operated todeliver a code made up of a series of code elements of selectedcharacters to said receiving station, said means including steppingapparatus operated progressively by successive elements of said code,means set into operation by a movement of said device out of agreementwith said relay for operating said transmitting means, a group ofregistering relays at said control station, means controlled by saidstepping apparatus for selectively energizing certainof said registeringrelays during the delivery of a code in accordance with the charactersof certain elements of such code, means for subsequently holding suchselected registering relays energized until the completion of the code,and means controlled by said registering relays for operating said relayinto agreement with the new position of said device.

56. In combination with a normally closed line circuit including a linerelay, a slow release relay arranged to become released if said linerelay remains energized for more than a predetermined time, a chain ofcounting relays, means effective only if said slow release relay remainspicked up for operating the relays of said chain progressively when saidline relay is operated repeatedly, and means controlled by said countingchain for repeatedly opening said line circuit in accordance with apredetermined code to operate said line relay.

5'7. In combination with a normally closed line circuit including a linerelay, a slow release relay arranged to become released if said linerelay remains energized for more than a predetermined time, a secondslow release relay arranged to become released if said line relay orsaid slow release relay remains deenergized for more than a.predetermined time, a chain of counting relays, means effective only ifsaid second slow releasing relay remains picked up for operating therelays of said chain progressively when said line relay is operatedrepeatedly, and means controlled by said counting relays for repeatedlyopening said line circuit in accordance with a predetermined code tooperate said line relay.

58. In combination with a line circuit including a line relay, a slowrelease relay arranged to become energized when said line relay isoperated, means for releasing said slow release relay if said line relayremains energized or remains deenergized for more than a predeterminedtime, transmitting means adapted to repeatedly interrupt said linecircuit to transmit a code over said line circuit, means effective onlywhen said slow release relay is deenergized to initiate the operation ofsaid transmitting means, and means efiective only if said slow releaserelay becomes energized to complete the operation of said transmittingmeans.

59. In combination with a normally closed line circuit including a linerelay, means for repeatedly opening said line circuit to produce adistinctive code, a first slow release relay arranged to become releasedif said line relay remains energized for more than a predetermined time,a second slow release relay arranged to become released if said linerelay of' said first slow release relay remain deenergized for more thana predetermined time, a chain of counting relays, means controlled bysaid line relay in response to said code and effective only if saidsecond slow release relay remains picked up to operate the relays ofsaid counting chain progressively, and receiving means controlled bysaid counting chain and selectively responsive to said code.

60. In combination with a line circuit including a line relay adapted toreceive code impulses, a slow release relay arranged to become energizedwhen said line relay is operated, means for releasing said slow releaserelay if said line relay remains energized or remains deenergized formore than a predetermined time, a chain of counting relays, means foroperating the relays of said chain progressively when said line relay isoperated repeatedly by the impulses of a code, provided said slowrelease relay remains picked up, and code receiving means controlled bysaid counting relays.

61. A combined code receiver and transmitter for a remote control systemhaving a line circuit at times supplied with a code of time spacedimpulses, a master relay, a transmitter for repeatedly interrupting theline circuit, a line relay in said line circuit, a series of contactsclosed sequentially as said line relay is operated repeatedly, aregister relay, means for picking up said register relay only when aselected contact of said series becomes closed, means rendered effectivewhen said master relay is picked up to set said transmitter intooperation, means rendered efiective when said register relay picks up totemporarily interrupt the operation of said transmitter to produce apause in the code, means effective if said master relay is deenergizedto prevent said register relay from picking up when the selected contactof said series becomes closed

